The nation's fourth biggest IVF company, City Fertility, has experienced a 30 per cent jump in inquiries from gay couples since same-sex marriage was legalised in December, offering growth opportunities for a company already super-charging its ambitions following a lucrative deal to sell a controlling stake to Asian buyers.

City Fertility founding partner and chief executive Adnan Catakovic will see his roughly 20 per cent holding in the company fall to around 4 per cent after clinching a deal with South Korea's CHA Healthcare and Singapore Medical Group to sell 65 per cent of the company.